ABSTRACT Risky alcohol use, sexually transmitted infections, and sexual violence in college student populations constitute highly prevalent and interrelated public health concerns. Although alcohol is associated with increased rates of STIs, more sex partners, sexual victimization, and decreased likelihood of condom use, no intervention to date has specifically targeted students? alcohol use, safe sex behavior, and sexual violence in an integrated package. The current dual-site proposal will develop and evaluate the initial efficacy of the Sex Positive Lifestyles: Addressing Alcohol & Sexual Health (SPLASH), an innovative tri-pronged group intervention that includes normative re-education to modify peer misperceptions, protective behavioral skills (PBS) training to increase drinking-related and sexual-risk protective behaviors, and bystander intervention training to reduce alcohol problems and sexual violence among college students aged 18-24. The intervention will use a sex- positive framework to educate students about shared contextual risk factors and address the influence of heavy alcohol use on protective and bystander behaviors. The components will be appropriate for students identifying as a sexual or gender minority. To refine SPLASH components, we will conduct focus groups (six groups, total N = 48) (Aim 1). We will use the refined protocol to conduct an open trial (n = 64) to pilot test enrollment and assessment methods; improve upon the clarity, content, acceptability, and feasibility; and evaluate participant acceptance of intervention components (Aim 2). We will then revise the intervention manual, procedures, and training protocol, and evaluate the feasibility, acceptability, and initial efficacy of the intervention in a randomized controlled pilot trial comparing the SPLASH intervention to a dose-matched attention control condition (total n = 110) (Aim 3). We will test preliminary hypotheses that SPLASH participants, relative to controls, will report reduced alcohol use and alcohol-related negative consequences, increased protective behaviors related to drinking and sex risk, reduced risky sex behaviors (fewer partners, fewer unprotected sex occasions, less alcohol before sex), and increased engagement in proactive bystander behavior and related outcomes (increased labeling of the problem and decreased barriers to intervention) at 3- and 6-months post-intervention. We will also explore if intervention effects are mediated by changes in perceived norms, intentions and self-efficacy to use PBS, and intentions and self-efficacy to engage in bystander behaviors. With an eye towards dissemination, we will interview campus stakeholders (N = 3 at each site) at the beginning and end of the project. There is a critical need for an empirically supported universal intervention that addresses interrelated risky drinking, unsafe sex, and sexual violence in college populations. This research will lay the groundwork for a cost-effective, integrated risky alcohol use, STI, and sexual violence prevention intervention for college students with the potential to be widely disseminated and maintained.